The onset of winter brings the familiar driving hazards of slippery roads from rain, ice and snow, conditions that can easily catch out the unprepared. Lexus SUV drivers can have the peace of mind of knowing their vehicle is equipped to automatically provide extra grip when the going gets tough.
E-Four is Lexus’s advanced all-wheel drive system, designed specifically to operate with its self-charging hybrid electric powertrains. Compact and lightweight, it avoids the drawbacks in weight, packaging, emissions and fuel consumption that are common with conventional, mechanical systems.
It uses an additional electric motor integrated with the rear differential to drive the rear axle, providing more grip and better vehicle control on slippery surfaces. The balance of power distributed between the car’s front and rear axles is determined by the Vehicle Stability Control system, with rear drive coming into play instantaneously when any wheelspin and loss of grip is detected. This intelligent operation – activating only when needed – also ensures there’s less impact on the car’s fuel economy and emissions.
The original E-Four system debuted in the UK on the first hybrid RX model, the RX 400h, in 2005. Since then its performance and capabilities have been constantly improved, most recently with a significant performance upgrade in 2018. This made 30 per cent more drive torque available to the rear wheels, enabling the vehicle to deal with more challenging low-grip conditions than before. An AWD Integrated Management system (AIM) ensures optimal power distribution.
The benefits of E-Four go beyond more secure performance in slippery conditions to help counter vehicle over and understeer, giving stable cornering performance with line-tracing faithful to the driver’s intentions. It also helps secure stable progress when pulling away on snow, sand or other tricky surfaces.
The rear motor additionally serves as a generator for the car’s regenerative braking system, increasing the amount of kinetic energy that can be captured when braking or decelerating and storing it as electric power in hybrid battery.
The latest version of E-Four is fitted as standard to all versions of the Lexus RX and seven-seat RX-L large luxury SUVs, and all versions of the NX mid-size model (with front-wheel drive an option for the entry-level version). On the UX 250h compact SUV, it is available on certain higher specification models.